This invention relates to the structure of a windshield wiper which supports a squeegee for wiping a windshield and which distributes pressure applied to the squeegee from the wiper arm. It is well known that such structures interfere with the natural air flow pattern created about a windshield when a vehicle moves at high speed and that in certain circumstances this interference will result in the windshield wiper being lifted away from the windshield with obviously undesirable consequences.
Wing attachments, secured to the windshield wiper body and shaped to redirect the air flow pattern so as to push the wiper against the windshied, are one of the kinds of structures which have been developed to address this problem. In other cases, the windshield wiper superstructure itself is profiled to disturb an oncoming air stream to cause a drag effect instead of a lift effect, for example in U.S. Pat. No. 4,400,845. In the structure of this patent, like many others, a major surface of the wiper is inclined relative to the windshield in use. In U.S. Pat. No. 4,852,206, the degree of inclination of this surface relative to the oncoming air stream varies along the length of the primary yoke. Another approach to the problem has been to provide apertures to allow air flow to pass through the structure as in U.S. Pat. No. 3,089,174 which illustrates a squeegee formed with a series of pressure relieving holes distributed along its length.
In some of the windshield wiper structures which carry an inclined surface for air flow control, it is recognized that air flow through the structure beneath the inclined surface will occur and operate to create a negative pressure thereby minimizing lift.
To applicant's knowledge no structure has been devised in which this through air, which in some orientations of the wiper must necessarily impinge on the wiper structure, is harnessed so as to positively push the wiper against the windshield.
The object of this invention is to provide a windshield wiper superstructure having an aerodynamic profile whereby the tendancy of a wiper to lift away from a windshield in use is minimized.